1. Field of the Invention
The present invention refers to a pallet for the storage and transport of various loads. More particularly, the invention refers to a constructive configuration of a pallet comprising a light, flexible and compression-resistant material.
2. Description of Related Art
A pallet used for storage and transport of loads can be evaluated by its functionality, performance and quality, by means of the analysis of the parameters such as mechanical resistance and size, static and dynamic stability, among others. Such parameters must meet the requirements established in accordance with the user's needs, handling and movement, and this involves two basic questions: the raw materials and the constructivity used in the assembly and manufacture of the pallet. However, the cost involved in production is a restricting factor for the scope of the pallet design. Often, a functional, efficient and good quality pallet having all the desirable characteristics is costly and its production is considered unfeasible.
Evaluation Parameters
Mechanical resistance is one of the determining factors of the total admissible load of the pallets. Both the raw materials used and the constructive configuration directly affect this matter. A pallet with low mechanical resistance has a low admissible load capacity, and may buckle or even become damaged depending on the total weight placed thereon, thus jeopardizing the safety of the load(s).
Size stability is achieved by using easy to handle raw materials that have low sensitivity in relation to climactic changes such as temperature and humidity. The production process may correct any size discrepancies, but this action involves cost and often the cost of repeated work is high because both allocation of specialized manpower and time could be used in other production processes.
Static stability is particularly important in stacking the loads on the pallet and in stacking the pallets on top of one another when not in use. The constructive configuration of the pallets should allow for a maximum quantity of stacked loads without risking their sliding or instability due to any constructive defect in the pallet interface. Therefore, the interface should not only have a physical space to place the loads, but also offer stability and safety for the loads themselves. The same can be said of the stacking of the pallets. Currently, it is commonplace to stack unused pallets in order to streamline space or to use them for other production purposes. The structure should be such that the pallet does not damage an another pallet beneath it.
Dynamic stability is related to the matter of slipping or sliding of the forks of the forklift trucks when inserting them into the pallets. Many currently known pallets are not able to maintain perfectly stability on the forks, and this may give rise to sliding and consequently damage the loads when the trucks move the pallets. The design of the pallet must also take into consideration other types of movement in which the pallet is subject during the production process such as, for example, transport via a conveyor belt that moves horizontally and vertically. Both the constructive configuration and the material used influence the dynamic stability, and a material having low attrition (friction) facilitates sliding.
The parameters explained above directly influence the various processes involved in handling pallets such as palletization (separation of stacked pallets and placement of loads on pallets), unitization (grouping of various lesser load volumes into a single larger volume on the pallet) and export (transport, movement and unloading of the pallet).
Raw Materials
The choice of raw materials is a fundamental and determinant stage for the pallet design, and it can become a limiting factor upon the design scope depending on the needs and requirements. The performance of the constructive configuration directly depends on the material used and vice-versa.
Most currently known pallets are built of wood or injected plastic.
The wooden parts have a relatively low manufacturing cost and also are easy to produce and structurally sound. However, this material presents certain problems such as fragility to attack by pests such as termites and the need to use nails or threads, which may damage the load placed upon the pallet, in joining the parts. Another drawback involves the difficulty of size control of the wood, and this fact may prejudice process automation besides creating difficulties in storing the pallets when not in use.
Despite the low manufacturing cost, wooden pallets may be costly due to the need to carry out the fumigation process, especially for exporting pallets. Fumigation consists of applying chemical products on the wood to disinfect the pallet, eliminating pests such as termites. This process is time-consuming and also costly, and adds to the final cost of the pallet as well as to the cost of transporting goods.
Lastly, the final disadvantage of wooden pallets concerns sustainability and environmental preservation. The use of wood causes deforestation and negatively impacts the environment. Therefore, the sustainability requirements are compromised, and the natural resource will potentially be depleted or become scarce.
Injected plastic parts have good durability, inherent pest resistance, and require no nails because generally injected plastic pallets are made in a single unit. However, this material has drawbacks such as low friction (instability), difficulty in repairing and the high cost involved in the manufacture of an injection mold. Thus, the production cost increases the final price of the pallet and, in most cases, the high cost of production of a plastic pallet makes its use unfeasible.
In this backdrop, it can be said that until the present invention there was no a pallet that brings together all the desired requirements and functionality at low cost. The user was often obliged to opt for certain characteristics whilst renouncing others due to the limitations dictated by cost, material and constructivity of the pallet.